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mariadb/storage/archive/azio.c
Sergei Golubchik fdcfc25127 Merge branch '10.3' into 10.4
2023-01-10 21:04:17 +01:00

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/*
azio is a modified version of gzio. It makes use of mysys and removes mallocs.
-Brian Aker
*/
/* gzio.c -- IO on .gz files
* Copyright (C) 1995-2005 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*
*/
/* @(#) $Id$ */
#include "azlib.h"
#include <stdio.h>
#include <string.h>
#include "my_sys.h"
static int const gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
static int const az_magic[3] = {0xfe, 0x03, 0x01}; /* az magic header */
/* gzip flag uchar */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define RESERVED 0xE0 /* bits 5..7: reserved */
int az_open(azio_stream *s, const char *path, int Flags, File fd);
int do_flush(azio_stream *file, int flush);
int get_byte(azio_stream *s);
void check_header(azio_stream *s);
int write_header(azio_stream *s);
int destroy(azio_stream *s);
void putLong(File file, uLong x);
uLong getLong(azio_stream *s);
void read_header(azio_stream *s, unsigned char *buffer);
#ifdef HAVE_PSI_INTERFACE
extern PSI_file_key arch_key_file_data;
#endif
/* ===========================================================================
Opens a gzip (.gz) file for reading or writing. The mode parameter
is as in fopen ("rb" or "wb"). The file is given either by file descriptor
or path name (if fd == -1).
az_open returns NULL if the file could not be opened or if there was
insufficient memory to allocate the (de)compression state; errno
can be checked to distinguish the two cases (if errno is zero, the
zlib error is Z_MEM_ERROR).
*/
int az_open (azio_stream *s, const char *path, int Flags, File fd)
{
int err;
int level = Z_DEFAULT_COMPRESSION; /* compression level */
int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */
s->stream.zalloc = my_az_allocator;
s->stream.zfree = my_az_free;
s->stream.opaque = (voidpf)0;
memset(s->inbuf, 0, AZ_BUFSIZE_READ);
memset(s->outbuf, 0, AZ_BUFSIZE_WRITE);
s->stream.next_in = s->inbuf;
s->stream.next_out = s->outbuf;
s->stream.avail_in = s->stream.avail_out = 0;
s->z_err = Z_OK;
s->z_eof = 0;
s->in = 0;
s->out = 0;
s->back = EOF;
s->crc = crc32(0L, Z_NULL, 0);
s->transparent = 0;
s->mode = 'r';
s->version = (unsigned char)az_magic[1]; /* this needs to be a define to version */
s->minor_version= (unsigned char) az_magic[2]; /* minor version */
s->dirty= AZ_STATE_CLEAN;
s->start= 0;
/*
We do our own version of append by nature.
We must always have write access to take card of the header.
*/
DBUG_ASSERT(Flags | O_APPEND);
DBUG_ASSERT(Flags | O_WRONLY);
if (Flags & O_RDWR)
s->mode = 'w';
if (s->mode == 'w')
{
err = deflateInit2(&(s->stream), level,
Z_DEFLATED, -MAX_WBITS, 8, strategy);
/* windowBits is passed < 0 to suppress zlib header */
s->stream.next_out = s->outbuf;
if (err != Z_OK)
{
destroy(s);
return Z_NULL;
}
} else {
s->stream.next_in = s->inbuf;
err = inflateInit2(&(s->stream), -MAX_WBITS);
/* windowBits is passed < 0 to tell that there is no zlib header.
* Note that in this case inflate *requires* an extra "dummy" byte
* after the compressed stream in order to complete decompression and
* return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are
* present after the compressed stream.
*/
if (err != Z_OK)
{
destroy(s);
return Z_NULL;
}
}
s->stream.avail_out = AZ_BUFSIZE_WRITE;
errno = 0;
s->file = fd < 0 ? mysql_file_open(arch_key_file_data, path, Flags, MYF(0)) : fd;
DBUG_EXECUTE_IF("simulate_archive_open_failure",
{
if (s->file >= 0)
{
my_close(s->file, MYF(0));
s->file= -1;
my_errno= EMFILE;
}
});
if (s->file < 0 )
{
destroy(s);
return Z_NULL;
}
if (Flags & O_CREAT || Flags & O_TRUNC)
{
s->rows= 0;
s->forced_flushes= 0;
s->shortest_row= 0;
s->longest_row= 0;
s->auto_increment= 0;
s->check_point= 0;
s->comment_start_pos= 0;
s->comment_length= 0;
s->frm_start_pos= 0;
s->frm_length= 0;
s->dirty= 1; /* We create the file dirty */
s->start = AZHEADER_SIZE + AZMETA_BUFFER_SIZE;
write_header(s);
my_seek(s->file, 0, MY_SEEK_END, MYF(0));
}
else if (s->mode == 'w')
{
uchar buffer[AZHEADER_SIZE + AZMETA_BUFFER_SIZE];
my_pread(s->file, buffer, AZHEADER_SIZE + AZMETA_BUFFER_SIZE, 0,
MYF(0));
read_header(s, buffer); /* skip the .az header */
my_seek(s->file, 0, MY_SEEK_END, MYF(0));
}
else
{
/* Reset values in case of old version of archive file */
s->rows= 0;
s->forced_flushes= 0;
s->shortest_row= 0;
s->longest_row= 0;
s->auto_increment= 0;
s->check_point= 0;
s->comment_start_pos= 0;
s->comment_length= 0;
s->frm_start_pos= 0;
s->frm_length= 0;
check_header(s); /* skip the .az header */
}
return 1;
}
int write_header(azio_stream *s)
{
char buffer[AZHEADER_SIZE + AZMETA_BUFFER_SIZE];
char *ptr= buffer;
if (s->version == 1)
return 0;
s->block_size= AZ_BUFSIZE_WRITE;
s->version = (unsigned char)az_magic[1];
s->minor_version = (unsigned char)az_magic[2];
/* Write a very simple .az header: */
memset(buffer, 0, AZHEADER_SIZE + AZMETA_BUFFER_SIZE);
*(ptr + AZ_MAGIC_POS)= az_magic[0];
*(ptr + AZ_VERSION_POS)= (unsigned char)s->version;
*(ptr + AZ_MINOR_VERSION_POS)= (unsigned char)s->minor_version;
*(ptr + AZ_BLOCK_POS)= (unsigned char)(s->block_size/1024); /* Reserved for block size */
*(ptr + AZ_STRATEGY_POS)= (unsigned char)Z_DEFAULT_STRATEGY; /* Compression Type */
int4store(ptr + AZ_FRM_POS, s->frm_start_pos); /* FRM Block */
int4store(ptr + AZ_FRM_LENGTH_POS, s->frm_length); /* FRM Block */
int4store(ptr + AZ_COMMENT_POS, s->comment_start_pos); /* COMMENT Block */
int4store(ptr + AZ_COMMENT_LENGTH_POS, s->comment_length); /* COMMENT Block */
int4store(ptr + AZ_META_POS, 0); /* Meta Block */
int4store(ptr + AZ_META_LENGTH_POS, 0); /* Meta Block */
int8store(ptr + AZ_START_POS, (unsigned long long)s->start); /* Start of Data Block Index Block */
int8store(ptr + AZ_ROW_POS, (unsigned long long)s->rows); /* Start of Data Block Index Block */
int8store(ptr + AZ_FLUSH_POS, (unsigned long long)s->forced_flushes); /* Start of Data Block Index Block */
int8store(ptr + AZ_CHECK_POS, (unsigned long long)s->check_point); /* Start of Data Block Index Block */
int8store(ptr + AZ_AUTOINCREMENT_POS, (unsigned long long)s->auto_increment); /* Start of Data Block Index Block */
int4store(ptr+ AZ_LONGEST_POS , s->longest_row); /* Longest row */
int4store(ptr+ AZ_SHORTEST_POS, s->shortest_row); /* Shorest row */
int4store(ptr+ AZ_FRM_POS,
AZHEADER_SIZE + AZMETA_BUFFER_SIZE); /* FRM position */
*(ptr + AZ_DIRTY_POS)= (unsigned char)s->dirty; /* Start of Data Block Index Block */
/* Always begin at the beginning, and end there as well */
return my_pwrite(s->file, (uchar*) buffer, AZHEADER_SIZE + AZMETA_BUFFER_SIZE,
0, MYF(MY_NABP)) ? 1 : 0;
}
/* ===========================================================================
Opens a gzip (.gz) file for reading or writing.
*/
int azopen(azio_stream *s, const char *path, int Flags)
{
return az_open(s, path, Flags, -1);
}
/* ===========================================================================
Associate a gzFile with the file descriptor fd. fd is not dup'ed here
to mimic the behavio(u)r of fdopen.
*/
int azdopen(azio_stream *s, File fd, int Flags)
{
if (fd < 0) return 0;
return az_open (s, NULL, Flags, fd);
}
/* ===========================================================================
Read a byte from a azio_stream; update next_in and avail_in. Return EOF
for end of file.
IN assertion: the stream s has been sucessfully opened for reading.
*/
int get_byte(azio_stream *s)
{
if (s->z_eof) return EOF;
if (s->stream.avail_in == 0)
{
errno = 0;
s->stream.avail_in= (uInt) mysql_file_read(s->file, (uchar *)s->inbuf,
AZ_BUFSIZE_READ, MYF(0));
if (s->stream.avail_in == 0)
{
s->z_eof = 1;
return EOF;
}
else if (s->stream.avail_in == (uInt) -1)
{
s->z_eof= 1;
s->z_err= Z_ERRNO;
return EOF;
}
s->stream.next_in = s->inbuf;
}
s->stream.avail_in--;
return *(s->stream.next_in)++;
}
/* ===========================================================================
Check the gzip header of a azio_stream opened for reading. Set the stream
mode to transparent if the gzip magic header is not present; set s->err
to Z_DATA_ERROR if the magic header is present but the rest of the header
is incorrect.
IN assertion: the stream s has already been created sucessfully;
s->stream.avail_in is zero for the first time, but may be non-zero
for concatenated .gz files.
*/
void check_header(azio_stream *s)
{
int method; /* method uchar */
int flags; /* flags uchar */
uInt len;
int c;
/* Assure two bytes in the buffer so we can peek ahead -- handle case
where first byte of header is at the end of the buffer after the last
gzip segment */
len = s->stream.avail_in;
if (len < 2) {
if (len) s->inbuf[0] = s->stream.next_in[0];
errno = 0;
len = (uInt)mysql_file_read(s->file, (uchar *)s->inbuf + len,
AZ_BUFSIZE_READ >> len, MYF(0));
if (len == (uInt)-1) s->z_err = Z_ERRNO;
s->stream.avail_in += len;
s->stream.next_in = s->inbuf;
if (s->stream.avail_in < 2) {
s->transparent = s->stream.avail_in;
return;
}
}
/* Peek ahead to check the gzip magic header */
if ( s->stream.next_in[0] == gz_magic[0] && s->stream.next_in[1] == gz_magic[1])
{
read_header(s, s->stream.next_in);
s->stream.avail_in -= 2;
s->stream.next_in += 2;
/* Check the rest of the gzip header */
method = get_byte(s);
flags = get_byte(s);
if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
s->z_err = Z_DATA_ERROR;
return;
}
/* Discard time, xflags and OS code: */
for (len = 0; len < 6; len++) (void)get_byte(s);
if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
len = (uInt)get_byte(s);
len += ((uInt)get_byte(s))<<8;
/* len is garbage if EOF but the loop below will quit anyway */
while (len-- != 0 && get_byte(s) != EOF) ;
}
if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
while ((c = get_byte(s)) != 0 && c != EOF) ;
}
if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
while ((c = get_byte(s)) != 0 && c != EOF) ;
}
if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
for (len = 0; len < 2; len++) (void)get_byte(s);
}
s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
if (!s->start)
s->start= my_tell(s->file, MYF(0)) - s->stream.avail_in;
}
else if ( s->stream.next_in[0] == az_magic[0] && s->stream.next_in[1] == az_magic[1])
{
unsigned char buffer[AZHEADER_SIZE + AZMETA_BUFFER_SIZE];
for (len = 0; len < (AZHEADER_SIZE + AZMETA_BUFFER_SIZE); len++)
buffer[len]= get_byte(s);
s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
read_header(s, buffer);
for (; len < s->start; len++)
get_byte(s);
}
else
{
s->z_err = Z_OK;
return;
}
}
void read_header(azio_stream *s, unsigned char *buffer)
{
if (buffer[0] == az_magic[0] && buffer[1] == az_magic[1])
{
uchar tmp[AZ_FRMVER_LEN + 2];
s->version= (unsigned int)buffer[AZ_VERSION_POS];
s->minor_version= (unsigned int)buffer[AZ_MINOR_VERSION_POS];
s->block_size= 1024 * buffer[AZ_BLOCK_POS];
s->start= (unsigned long long)uint8korr(buffer + AZ_START_POS);
s->rows= (unsigned long long)uint8korr(buffer + AZ_ROW_POS);
s->check_point= (unsigned long long)uint8korr(buffer + AZ_CHECK_POS);
s->forced_flushes= (unsigned long long)uint8korr(buffer + AZ_FLUSH_POS);
s->auto_increment= (unsigned long long)uint8korr(buffer + AZ_AUTOINCREMENT_POS);
s->longest_row= (unsigned int)uint4korr(buffer + AZ_LONGEST_POS);
s->shortest_row= (unsigned int)uint4korr(buffer + AZ_SHORTEST_POS);
s->frm_start_pos= (unsigned int)uint4korr(buffer + AZ_FRM_POS);
s->frm_length= (unsigned int)uint4korr(buffer + AZ_FRM_LENGTH_POS);
s->comment_start_pos= (unsigned int)uint4korr(buffer + AZ_COMMENT_POS);
s->comment_length= (unsigned int)uint4korr(buffer + AZ_COMMENT_LENGTH_POS);
s->dirty= (unsigned int)buffer[AZ_DIRTY_POS];
/*
we'll hard-code the current frm format for now, to avoid
changing archive table versions.
*/
if (s->frm_length == 0 ||
my_pread(s->file, tmp, sizeof(tmp), s->frm_start_pos + 64, MYF(MY_NABP)) ||
tmp[0] != 0 || tmp[1] != AZ_FRMVER_LEN)
{
s->frmver_length= 0;
}
else
{
s->frmver_length= tmp[1];
memcpy(s->frmver, tmp+2, s->frmver_length);
}
}
else if (buffer[0] == gz_magic[0] && buffer[1] == gz_magic[1])
{
/*
Set version number to previous version (1).
*/
s->version= 1;
s->auto_increment= 0;
s->frm_length= 0;
s->longest_row= 0;
s->shortest_row= 0;
} else {
/*
Unknown version.
Most probably due to a corrupt archive.
*/
s->dirty= AZ_STATE_DIRTY;
s->z_err= Z_VERSION_ERROR;
}
}
/* ===========================================================================
* Cleanup then free the given azio_stream. Return a zlib error code.
Try freeing in the reverse order of allocations.
*/
int destroy (azio_stream *s)
{
int err = Z_OK;
if (s->stream.state != NULL)
{
if (s->mode == 'w')
err = deflateEnd(&(s->stream));
else if (s->mode == 'r')
err = inflateEnd(&(s->stream));
}
if (s->file > 0 && my_close(s->file, MYF(0)))
err = Z_ERRNO;
s->file= -1;
if (s->z_err < 0) err = s->z_err;
return err;
}
/* ===========================================================================
Reads the given number of uncompressed bytes from the compressed file.
azread returns the number of bytes actually read (0 for end of file).
*/
unsigned int ZEXPORT azread ( azio_stream *s, voidp buf, size_t len, int *error)
{
Bytef *start = (Bytef*)buf; /* starting point for crc computation */
Byte *next_out; /* == stream.next_out but not forced far (for MSDOS) */
*error= 0;
if (s->mode != 'r')
{
*error= Z_STREAM_ERROR;
return 0;
}
if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO)
{
*error= s->z_err;
return 0;
}
if (s->z_err == Z_STREAM_END) /* EOF */
{
return 0;
}
next_out = (Byte*)buf;
s->stream.next_out = (Bytef*)buf;
s->stream.avail_out = (uInt)len;
if (s->stream.avail_out && s->back != EOF) {
*next_out++ = s->back;
s->stream.next_out++;
s->stream.avail_out--;
s->back = EOF;
s->out++;
start++;
if (s->last) {
s->z_err = Z_STREAM_END;
{
return 1;
}
}
}
while (s->stream.avail_out != 0) {
if (s->transparent) {
/* Copy first the lookahead bytes: */
uInt n = s->stream.avail_in;
if (n > s->stream.avail_out) n = s->stream.avail_out;
if (n > 0) {
memcpy(s->stream.next_out, s->stream.next_in, n);
next_out += n;
s->stream.next_out = (Bytef *)next_out;
s->stream.next_in += n;
s->stream.avail_out -= n;
s->stream.avail_in -= n;
}
if (s->stream.avail_out > 0)
{
s->stream.avail_out -=
(uInt)mysql_file_read(s->file, (uchar *)next_out,
s->stream.avail_out, MYF(0));
}
len -= s->stream.avail_out;
s->in += len;
s->out += len;
if (len == 0) s->z_eof = 1;
{
return (uint)len;
}
}
if (s->stream.avail_in == 0 && !s->z_eof) {
errno = 0;
s->stream.avail_in = (uInt)mysql_file_read(s->file, (uchar *)s->inbuf,
AZ_BUFSIZE_READ, MYF(0));
if (s->stream.avail_in == 0)
{
s->z_eof = 1;
}
s->stream.next_in = (Bytef *)s->inbuf;
}
s->in += s->stream.avail_in;
s->out += s->stream.avail_out;
s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
s->in -= s->stream.avail_in;
s->out -= s->stream.avail_out;
if (s->z_err == Z_STREAM_END) {
/* Check CRC and original size */
s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
start = s->stream.next_out;
if (getLong(s) != s->crc) {
s->z_err = Z_DATA_ERROR;
} else {
(void)getLong(s);
/* The uncompressed length returned by above getlong() may be
* different from s->out in case of concatenated .gz files.
* Check for such files:
*/
check_header(s);
if (s->z_err == Z_OK)
{
inflateReset(&(s->stream));
s->crc = crc32(0L, Z_NULL, 0);
}
}
}
if (s->z_err != Z_OK || s->z_eof) break;
}
s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
if (len == s->stream.avail_out &&
(s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO))
{
*error= s->z_err;
return 0;
}
return (uint)(len - s->stream.avail_out);
}
/* ===========================================================================
Writes the given number of uncompressed bytes into the compressed file.
azwrite returns the number of bytes actually written (0 in case of error).
*/
unsigned int azwrite (azio_stream *s, const voidp buf, unsigned int len)
{
s->stream.next_in = (Bytef*)buf;
s->stream.avail_in = len;
s->rows++;
while (s->stream.avail_in != 0)
{
if (s->stream.avail_out == 0)
{
s->stream.next_out = s->outbuf;
if (mysql_file_write(s->file, (uchar *)s->outbuf, AZ_BUFSIZE_WRITE,
MYF(0)) != AZ_BUFSIZE_WRITE)
{
s->z_err = Z_ERRNO;
break;
}
s->stream.avail_out = AZ_BUFSIZE_WRITE;
}
s->in += s->stream.avail_in;
s->out += s->stream.avail_out;
s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
s->in -= s->stream.avail_in;
s->out -= s->stream.avail_out;
if (s->z_err != Z_OK) break;
}
s->crc = crc32(s->crc, (const Bytef *)buf, len);
if (len > s->longest_row)
s->longest_row= len;
if (len < s->shortest_row || !(s->shortest_row))
s->shortest_row= len;
return (unsigned int)(len - s->stream.avail_in);
}
/* ===========================================================================
Flushes all pending output into the compressed file. The parameter
flush is as in the deflate() function.
*/
int do_flush (azio_stream *s, int flush)
{
uInt len;
int done = 0;
my_off_t afterwrite_pos;
if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
s->stream.avail_in = 0; /* should be zero already anyway */
for (;;)
{
len = AZ_BUFSIZE_WRITE - s->stream.avail_out;
if (len != 0)
{
s->check_point= my_tell(s->file, MYF(0));
if ((uInt)mysql_file_write(s->file, (uchar *)s->outbuf, len, MYF(0)) != len)
{
s->z_err = Z_ERRNO;
return Z_ERRNO;
}
s->stream.next_out = s->outbuf;
s->stream.avail_out = AZ_BUFSIZE_WRITE;
}
if (done) break;
s->out += s->stream.avail_out;
s->z_err = deflate(&(s->stream), flush);
s->out -= s->stream.avail_out;
/* Ignore the second of two consecutive flushes: */
if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;
/* deflate has finished flushing only when it hasn't used up
* all the available space in the output buffer:
*/
done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);
if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
}
if (flush == Z_FINISH)
s->dirty= AZ_STATE_CLEAN; /* Mark it clean, we should be good now */
else
s->dirty= AZ_STATE_SAVED; /* Mark it clean, we should be good now */
afterwrite_pos= my_tell(s->file, MYF(0));
write_header(s);
my_seek(s->file, afterwrite_pos, SEEK_SET, MYF(0));
return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
}
int ZEXPORT azflush (azio_stream *s, int flush)
{
int err;
if (s->mode == 'r')
{
unsigned char buffer[AZHEADER_SIZE + AZMETA_BUFFER_SIZE];
my_pread(s->file, (uchar*) buffer, AZHEADER_SIZE + AZMETA_BUFFER_SIZE, 0,
MYF(0));
read_header(s, buffer); /* skip the .az header */
return Z_OK;
}
else
{
s->forced_flushes++;
err= do_flush(s, flush);
if (err) return err;
my_sync(s->file, MYF(0));
return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
}
}
/* ===========================================================================
Rewinds input file.
*/
int azrewind (azio_stream *s)
{
if (s == NULL || s->mode != 'r') return -1;
s->z_err = Z_OK;
s->z_eof = 0;
s->back = EOF;
s->stream.avail_in = 0;
s->stream.next_in = (Bytef *)s->inbuf;
s->crc = crc32(0L, Z_NULL, 0);
if (!s->transparent) (void)inflateReset(&s->stream);
s->in = 0;
s->out = 0;
return my_seek(s->file, (int)s->start, MY_SEEK_SET, MYF(0)) == MY_FILEPOS_ERROR;
}
/* ===========================================================================
Sets the starting position for the next azread or azwrite on the given
compressed file. The offset represents a number of bytes in the
azseek returns the resulting offset location as measured in bytes from
the beginning of the uncompressed stream, or -1 in case of error.
SEEK_END is not implemented, returns error.
In this version of the library, azseek can be extremely slow.
*/
my_off_t azseek (azio_stream *s, my_off_t offset, int whence)
{
if (s == NULL || whence == SEEK_END ||
s->z_err == Z_ERRNO || s->z_err == Z_DATA_ERROR) {
return -1L;
}
if (s->mode == 'w')
{
if (whence == SEEK_SET)
offset -= s->in;
/* At this point, offset is the number of zero bytes to write. */
/* There was a zmemzero here if inbuf was null -Brian */
while (offset > 0)
{
uInt size = AZ_BUFSIZE_READ;
if (offset < AZ_BUFSIZE_READ) size = (uInt)offset;
size = azwrite(s, s->inbuf, size);
if (size == 0) return -1L;
offset -= size;
}
return s->in;
}
/* Rest of function is for reading only */
/* compute absolute position */
if (whence == SEEK_CUR) {
offset += s->out;
}
if (s->transparent) {
/* map to my_seek */
s->back = EOF;
s->stream.avail_in = 0;
s->stream.next_in = (Bytef *)s->inbuf;
if (my_seek(s->file, offset, MY_SEEK_SET, MYF(0)) == MY_FILEPOS_ERROR) return -1L;
s->in = s->out = offset;
return offset;
}
/* For a negative seek, rewind and use positive seek */
if (offset >= s->out) {
offset -= s->out;
} else if (azrewind(s)) {
return -1L;
}
/* offset is now the number of bytes to skip. */
if (offset && s->back != EOF) {
s->back = EOF;
s->out++;
offset--;
if (s->last) s->z_err = Z_STREAM_END;
}
while (offset > 0) {
int error;
unsigned int size = AZ_BUFSIZE_WRITE;
if (offset < AZ_BUFSIZE_WRITE) size = (int)offset;
size = azread(s, s->outbuf, size, &error);
if (error < 0) return -1L;
offset -= size;
}
return s->out;
}
/* ===========================================================================
Returns the starting position for the next azread or azwrite on the
given compressed file. This position represents a number of bytes in the
uncompressed data stream.
*/
my_off_t ZEXPORT aztell (azio_stream *file)
{
return azseek(file, 0L, SEEK_CUR);
}
/* ===========================================================================
Outputs a long in LSB order to the given file
*/
void putLong (File file, uLong x)
{
int n;
uchar buffer[1];
for (n = 0; n < 4; n++)
{
buffer[0]= (int)(x & 0xff);
mysql_file_write(file, buffer, 1, MYF(0));
x >>= 8;
}
}
/* ===========================================================================
Reads a long in LSB order from the given azio_stream. Sets z_err in case
of error.
*/
uLong getLong (azio_stream *s)
{
uLong x = (uLong)get_byte(s);
int c;
x += ((uLong)get_byte(s))<<8;
x += ((uLong)get_byte(s))<<16;
c = get_byte(s);
if (c == EOF) s->z_err = Z_DATA_ERROR;
x += ((uLong)c)<<24;
return x;
}
/* ===========================================================================
Flushes all pending output if necessary, closes the compressed file
and deallocates all the (de)compression state.
*/
int azclose (azio_stream *s)
{
if (s == NULL) return Z_STREAM_ERROR;
if (s->file < 1) return Z_OK;
if (s->mode == 'w')
{
if (do_flush(s, Z_FINISH) != Z_OK)
{
destroy(s);
return Z_ERRNO;
}
putLong(s->file, s->crc);
putLong(s->file, (uLong)(s->in & 0xffffffff));
s->dirty= AZ_STATE_CLEAN;
s->check_point= my_tell(s->file, MYF(0));
write_header(s);
}
return destroy(s);
}
/*
Though this was added to support MySQL's FRM file, anything can be
stored in this location.
*/
int azwrite_frm(azio_stream *s, const uchar *blob, size_t length)
{
if (s->mode == 'r')
return 1;
if (s->rows > 0)
return 1;
s->frm_start_pos= (uint) s->start;
s->frm_length= (uint)length;
s->start+= length;
if (my_pwrite(s->file, blob, s->frm_length,
s->frm_start_pos, MYF(MY_NABP)) ||
write_header(s) ||
(my_seek(s->file, 0, MY_SEEK_END, MYF(0)) == MY_FILEPOS_ERROR))
return 1;
return 0;
}
int azread_frm(azio_stream *s, uchar *blob)
{
return my_pread(s->file, blob, s->frm_length,
s->frm_start_pos, MYF(MY_NABP)) ? 1 : 0;
}
/*
Simple comment field
*/
int azwrite_comment(azio_stream *s, const char *blob, size_t length)
{
if (s->mode == 'r')
return 1;
if (s->rows > 0)
return 1;
s->comment_start_pos= (uint) s->start;
s->comment_length= (uint)length;
s->start+= length;
my_pwrite(s->file, (uchar*) blob, s->comment_length, s->comment_start_pos,
MYF(0));
write_header(s);
my_seek(s->file, 0, MY_SEEK_END, MYF(0));
return 0;
}
int azread_comment(azio_stream *s, char *blob)
{
my_pread(s->file, (uchar*) blob, s->comment_length, s->comment_start_pos,
MYF(0));
return 0;
}
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